<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        /*id选择器*/
        #mydiv{
            color: red;
        }
        /*类选择器*/
        .c1{
            color: blue;
        }
        /*分组选择器*/
        h1,#mydiv,.c1{
            background-color: yellow;
        }
        /*属性选择器*/
        [type]{
            color: red;
        }
        [type="text"]{
            background-color: green;
        }
        /*任意元素选择器*/
        *{
              /*边框:粗细 实线 颜色*/
            border: 1px solid red;
        }
    </style>
</head>
<body>
<input type="text">
<input type="password">
<div id="mydiv">div1</div>
<div>div2</div>
<div class="c1">div3</div>
<span>span1</span>
<span>span2</span>
<span class="c1">span3</span>
<h1>我是h1</h1>
</body>
</html>